title: Prevalence of acute mountain sickness in the Swiss Alps.
abstract: OBJECTIVE
  To assess the prevalence of symptoms and signs of acute mountain sickness of the Swiss Alps.
  
  
  METHODS
  A study using an interview and clinical examination in a representative population of mountaineers. Positive symptoms and signs were assigned scores to quantify the severity of acute mountain sickness.
  
  
  METHODS
  Four huts in the Swiss Alps at 2850 m, 3050 m, 3650 m, and 4559 m.
  
  
  METHODS
  466 Climbers, mostly recreational: 47 at 2850 m, 128 at 3050 m, 82 at 3650, and 209 at 4559 m.
  
  
  RESULTS
  In all, 117 of the subjects were entirely free of symptoms and clinical signs of acute mountain sickness; 191 had one or two symptoms and signs; and 158 had more than two. Those with more than two symptoms and signs were defined as suffering from acute mountain sickness. At 4559 m 11 climbers presented with high altitude pulmonary oedema or cerebral oedema, or both. Men and women were equally affected. The prevalence of acute mountain sickness correlated with altitude: it was 9% at 2850 m, 13% at 3050 m, 34% at 3650 m, and 53% at 4559 m. The most frequent symptoms and signs were insomnia, headache, peripheral oedema, and scanty pulmonary rales. Severe headache, vomiting, dizziness, tachypnoea, and pronounced pulmonary rales were associated with other symptoms and signs and therefore characteristic of acute mountain sickness.
  
  
  CONCLUSIONS
  Acute mountain sickness is not an uncommon disease at moderately high altitude--that is, above 2800 m. Severe headache, vomiting, dizziness, tachypnoea, and pronounced pulmonary rales indicate severe acute mountain sickness, and subjects who suffer these should immediately descend to lower altitudes.
authors.affiliation: Department of Medicine, University Hospital Zürich.
authors.forename: M
authors.initials: M
authors.lastname: Maggiorini
authors.forename: B
authors.initials: B
authors.lastname: Bühler
authors.forename: M
authors.initials: M
authors.lastname: Walter
authors.forename: O
authors.initials: O
authors.lastname: Oelz
mesh_terms: D000208:Acute Disease; D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000150:complications / Q000453:epidemiology*; D001929:Brain Edema / Q000209:etiology; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D015995:Prevalence; D011654:Pulmonary Edema / Q000209:etiology; D012720:Severity of Illness Index; D013557:Switzerland / Q000453:epidemiology